AP Stats Stats: Evaluation Content and Structure 2

Question 1

A researcher surveys every 10th student on an alphabetical class roster. What type of sampling method is this?

Accepted Answer

Systematic sampling

Answer

Systematic sampling selects every kth element from an ordered list after a random start.

Question 2

Which of the following best describes a confounding variable in an experiment?

Accepted Answer

A variable related to both the explanatory and response variable that can distort results

Answer

A confounding variable is associated with both the explanatory variable and the response, making it hard to determine causation.

Question 3

In an observational study comparing incomes of college graduates vs. non-graduates, why can't we conclude that college causes higher income?

Accepted Answer

Lurking variables such as family background may explain the difference

Answer

Observational studies cannot establish causation because lurking variables may drive any observed association.

Question 4

A study randomly assigns participants to treatment and control groups. This design feature primarily controls for:

Accepted Answer

Confounding variables

Answer

Random assignment balances both known and unknown confounding variables across treatment groups.

Question 5

Which of the following is an example of a double-blind experiment?

Accepted Answer

Neither the subjects nor the researchers know who received which treatment

Answer

Double-blind means both participants and those measuring outcomes are unaware of treatment assignments.

AP Practice Test